Thermal stability and inactivation of hepatitis C virus grown in cell culture

Abstract

BackgroundHepatitis C virus (HCV) is a blood-borne flavivirus that infects many millions of people worldwide. Relatively little is known, however, concerning the stability of HCV and reliable procedures for inactivating this virus.MethodsIn the current study, the thermostability of cell culture-derived HCV (HCVcc, JFH-1 strain) under different environmental temperatures (37°C, room temperature, and 4°C) and the ability of heat, UVC light irradiation, and aldehyde and detergent treatments to inactivate HCVcc were evaluated. The infectious titers of treated viral samples were determined by focus-forming unit (FFU) assay using an indirect immunofluorescence assay for HCV NS3 in hepatoma Huh7-25-CD81 cells highly permissive for HCVcc infection. MTT cytotoxicity assay was performed to determine the concentrations of aldehydes or detergents at which they were no longer cytotoxic.ResultsHCVcc in culture medium was found to survive 37°C and room temperature (RT, 25 ± 2°C) for 2 and 16 days, respectively, while the virus was relatively stable at 4°C without drastic loss of infectivity for at least 6 weeks. HCVcc in culture medium was sensitive to heat and could be inactivated in 8 and 4 min when incubated at 60°C and 65°C, respectively. However, at 56°C, 40 min were required to eliminate HCVcc infectivity. Addition of normal human serum to HCVcc did not significantly alter viral stability at RT or its susceptibility to heat. UVC light irradiation (wavelength = 253.7 nm) with an intensity of 450 μW/cm2 efficiently inactivated HCVcc within 2 min. Exposures to formaldehyde, glutaraldehyde, ionic or nonionic detergents all destroyed HCVcc infectivity effectively, regardless of whether the treatments were conducted in the presence of cell culture medium or human serum.ConclusionsThe results provide quantitative evidence for the potential use of a variety of approaches for inactivating HCV. The ability of HCVcc to survive ambient temperatures warrants precautions in handling and disposing of objects and materials that may have been contaminated with HCV.

Entry and replication of recombinant hepatitis C viruses in cell culture

“…Briefly, we found that HCVcc (Jc1 or Luc-Jc1 virus) has a half-life of 6 hours at 37°C, 3.5 days at room temperature and 11 days at 4°C [178]. Other teams reported JFH-1 virus stability at 4°C for up to 4 or 6 weeks [6,190], a difference that might be imputable to the different virus strains and titers. To our knowledge, HCVcc stability at -80°C over long-term storage has not been documented, but HCVcc stored at -80°C can undergo up to 5 cycles of freeze-thaw without a significant loss of infectivity [6,190].…”

“…Other teams reported JFH-1 virus stability at 4°C for up to 4 or 6 weeks [6,190], a difference that might be imputable to the different virus strains and titers. To our knowledge, HCVcc stability at -80°C over long-term storage has not been documented, but HCVcc stored at -80°C can undergo up to 5 cycles of freeze-thaw without a significant loss of infectivity [6,190]. Nevertheless, Yi recommends supplementing the medium with 20% foetal calf serum prior to HCVcc freezing [56].…”

Inactivation of Human Rhinovirus due to Heat, UV Irradiation and Chemical Disinfectants

“…Heat-inactivated virus exhibits denatured viral proteins and dissociated viral particles into noninfectious viral subunits [11]. Many viruses, such as avian influenza A (H7N9), HCV, and EBOV have been shown to be sensitive to heat treatment [12][13][14]. In this study, an analysis was conducted on the inactivation of HRV at various environmental temperatures.…”

Usutuvirus

“…Man kann nach den bisher bekannten Daten zur Stabilität verschiedener Flaviviren wie DENV, YFV, FSMEV und WNV davon ausgehen, dass sich USUV vergleichbar zu diesen Flaviviren im Hinblick auf die Thermostabilität und Empfindlichkeit gegen Alkohole und Detergenzien verhält [14,15,16,17,18]. Detergensbehandlung und Behandlung bei niedrigem pH, wie sie bei der Herstellung von Plasmaprodukten verwendet werden, inaktivieren WNV und scheinen daher auch geeignet, USUV zu inaktivieren [19].…”